1. Field of the Invention
The present invention generally relates to transmitters. The present invention specifically relates to dynamic biasing of currents within a transmitter chip.
2. Description of the Related Art
In a transmitter chip, a current for biasing each block of the transmitter chip is a function of the required linearity and the output power. Some transmitter chips have the ability to dynamically adjust the output power. Consequently, the biasing current can be dynamically adjusted to reduce the total current consumption of the transmitter.
There are currently two techniques for dynamically adjusting a biasing current. The first technique involves a reading of a lookup table of biasing current settings whenever the output power is altered, and changing the biasing current accordingly. The second technique involves measuring the output power and dynamically generating appropriate biasing voltage and biasing currents as a function of the measured output power. Neither of these techniques is immune to any variations in a temperature, a supply power, and a processing performance of the transmitter chip. Additionally, neither of these techniques can continually keep the overall gain of the transmitter chip constant as the bias currents are dynamically adjusted. Thus, prior to the present, an efficient and effective technique for dynamically adjusting a biasing current while maintaining a constant overall gain was not achieved.